Sodium Bicarbonate in Cardiac Arrest: Evidence-Based Recommendations
Routine administration of sodium bicarbonate during cardiac arrest is NOT recommended and may worsen outcomes. 1, 2
Why Routine Use Is Harmful
The evidence against routine sodium bicarbonate administration during cardiac arrest is compelling:
- No improvement in survival: Multiple studies show no benefit in return of spontaneous circulation (ROSC), hospital admission rates, or survival to discharge when bicarbonate is used routinely 1, 2, 3
- Associated with worse outcomes: Observational data consistently demonstrate lower ROSC rates and decreased survival when bicarbonate is administered during pediatric and adult cardiac arrest 1
- Physiologic harm: Bicarbonate creates multiple adverse effects that may worsen cardiac arrest outcomes 2:
- Compromises coronary perfusion pressure by reducing systemic vascular resistance 2
- Produces extracellular alkalosis that shifts the oxyhemoglobin curve and inhibits oxygen release to tissues 2
- Generates excess CO₂ that diffuses into myocardial and cerebral cells, causing paradoxical intracellular acidosis 1, 2
- Causes hypernatremia and hyperosmolarity 1, 2
- Inactivates simultaneously administered catecholamines (epinephrine, norepinephrine) 1, 2
- Produces hypokalemia and hypocalcemia 1
When Sodium Bicarbonate IS Indicated During Cardiac Arrest
Sodium bicarbonate should be reserved for specific clinical scenarios only 1, 4, 2:
1. Hyperkalemic Cardiac Arrest (Class IIb indication)
- Administer 1 mEq/kg (50-100 mEq) IV push to shift potassium intracellularly 1, 4
- Use in conjunction with other hyperkalemia treatments (insulin/glucose, calcium) 4
2. Tricyclic Antidepressant (TCA) Overdose with Cardiotoxicity (Class I indication)
- Strongest indication: Life-threatening cardiac conduction delays with QRS >120 ms 4, 2
- Give hypertonic sodium bicarbonate (1000 mEq/L solution) as 50-150 mEq IV bolus 4
- Target arterial pH 7.45-7.55 4
- Continue infusion of 150 mEq/L solution at 1-3 mL/kg/hour to maintain alkalosis 4
3. Sodium Channel Blocker Toxicity (Class IIa indication)
- Similar dosing to TCA overdose: 50-150 mEq bolus, then infusion 4
- Titrate to resolution of QRS prolongation and hemodynamic stability 4
4. Documented Severe Metabolic Acidosis (Class IIb indication)
- Only after first dose of epinephrine fails in prolonged arrest 1, 4
- Requires arterial pH <7.1 AND effective ventilation already established 1, 4
- Give 1 mEq/kg (1 mmol/kg) as single bolus before second epinephrine dose 4
5. Prolonged Cardiac Arrest (>10-20 minutes)
- May be considered in refractory arrest with severe acidosis, but evidence is weak 1, 5
- Must ensure adequate ventilation first 1
Recommended Dosing When Indicated
Initial Bolus Dose 1, 4, 6:
- Adults: 1-2 mEq/kg IV (typically 50-100 mL of 8.4% solution = 44.6-100 mEq)
- Children: 1-2 mEq/kg IV given slowly
- Infants <2 years: Use only 0.5 mEq/mL (4.2%) concentration—dilute 8.4% solution 1:1 with normal saline 1, 4
Repeat Dosing 6:
- In cardiac arrest: 50 mL (44.6-50 mEq) every 5-10 minutes as indicated by arterial pH monitoring
- Target pH 7.2-7.3, NOT complete normalization 4, 6
- Guide therapy with arterial blood gas analysis, not empirically 4
Continuous Infusion (for TCA/sodium channel blocker toxicity) 4:
- Prepare 150 mEq/L solution
- Infuse at 1-3 mL/kg/hour
- Monitor to avoid serum sodium >150-155 mEq/L and pH >7.50-7.55 4
Critical Administration Guidelines
Before Giving Bicarbonate 1, 4:
- Ensure effective ventilation is established—bicarbonate produces CO₂ that MUST be eliminated to prevent worsening intracellular acidosis 1
- Flush IV line with normal saline before and after administration 4
- Never mix with:
During Administration 4:
- Give as slow IV push over several minutes, not rapid bolus
- Monitor continuously for dysrhythmias
Monitoring Requirements 4:
- Arterial blood gases every 2-4 hours
- Serum electrolytes (sodium, potassium, calcium) every 2-4 hours
- Avoid serum sodium >150-155 mEq/L
- Avoid pH >7.50-7.55
- Replace potassium as needed (bicarbonate causes intracellular K⁺ shift)
What Actually Works in Cardiac Arrest
The mainstays of acid-base restoration during cardiac arrest are 2:
- High-quality chest compressions to restore tissue perfusion
- Effective ventilation with oxygen to eliminate CO₂
- Rapid achievement of ROSC through defibrillation (if shockable rhythm) and appropriate medications (epinephrine)
Common Pitfalls to Avoid
- Do NOT give bicarbonate routinely "just because the arrest is prolonged" 1
- Do NOT give bicarbonate for respiratory acidosis—treat with ventilation 4
- Do NOT give bicarbonate without adequate ventilation—you will worsen intracellular acidosis 1
- Do NOT attempt complete pH normalization—target 7.2-7.3 only 4, 6
- Do NOT give bicarbonate for lactic acidosis with pH ≥7.15—no benefit and potential harm 4
Special Populations
Pediatric Dosing 1:
- Standard dose: 1-2 mEq/kg IV given slowly
- Newborns: Only 0.5 mEq/mL (4.2%) concentration
- Maximum single dose: 1 mg (for epinephrine comparison)
- Same indications as adults: NOT routine, only for hyperkalemia, severe acidosis, or toxidromes
Neonatal Resuscitation 1:
- Routine administration NOT recommended
- No improvement in survival demonstrated in neonatal respiratory arrest 1
Summary Algorithm
During cardiac arrest, ask these questions in order:
- Is this hyperkalemic arrest? → YES: Give bicarbonate 1 mEq/kg 1
- Is this TCA/sodium channel blocker overdose with QRS >120 ms? → YES: Give hypertonic bicarbonate 50-150 mEq bolus 4, 2
- Has first dose of epinephrine failed AND is pH <7.1 AND is ventilation adequate? → YES: Consider 1 mEq/kg bolus 1, 4
- None of the above? → NO bicarbonate—focus on compressions, ventilation, and achieving ROSC 2
The evidence is clear: sodium bicarbonate does not improve outcomes in routine cardiac arrest and may cause harm through multiple physiologic mechanisms. 1, 2, 3